Timken389-3Tapered Roller Bearing Cone – 2.1880 in Bore, 0.8640 in Width, Class 3, K Factor 1.65

Product Description

What this part is:

Timken 389-3 tapered roller bearing cone. This is the inner ring with its tapered roller set and cage, the rotating half of a Timken TS single-row inch tapered roller bearing, built to Class 3 precision. Bore Diameter: 2.1880 in (55.575 mm). Overall Width: 0.8640 in (21.946 mm) inner ring width. Item Weight: 2.56 kg (5.64 lb). Dynamic Load Rating: 108,000 N (24,200 lbf) at C1. Static Load Rating: 107,000 N (24,100 lbf). Precision Class: Class 3. Rolling Elements: Tapered Roller. Number Of Rows: 1. Bore Type: Straight. Cage Type: Pressed. Bearing Material: case-carburized alloy steel. Design Units: Imperial. Series: 380. Base Number: 389.

Decoding the designation:

389 — a cone number in Timken’s inch 380 tapered roller series, fixing the 2.1880 in bore and the 0.8640 in inner ring width.

-3 — Precision Class 3, also written *3 and #3. A tighter tolerance than standard, giving lower running vibration and closer location of the shaft. The class changes tolerance only; bore, width, raceway angle and load ratings are those of the 389.

What these specs mean in practice:

K Factor: 1.65. A K factor of 1.65 is a moderate taper: radial load dominates, with a useful thrust reserve. That is the general-purpose profile for a shaft carried on an opposed pair.

Dynamic Load Rating: 108,000 N (C1, at 1 million revolutions, ISO method). Static Load Rating: 107,000 N. Dynamic Radial Load Rating at 90 million revolutions (C90): 28,000 N. Dynamic Axial Rating at 90 million revolutions (Ca90): 16,900 N. On this cone the static and dynamic radial figures sit within one per cent of each other, so a duty that is limited by shock load is limited at essentially the same number as one limited by fatigue life.

G1 Factor: 42. G2 Factor: 15.7. Geometry Factor (Cg): 0.0859, the geometry constant for the lubrication life adjustment factor a3l.

Mounting data:

Maximum Shaft Fillet Radius: 0.09 in (2.3 mm) — the largest fillet the shaft shoulder may carry and still be cleared by the cone corner. Shaft Backing Shoulder Diameter, frontface (da): 2.40 in (61 mm). Shaft Backing Shoulder Diameter, backface (db): 2.56 in (65 mm). Effective Centre Location: -0.12 in (-3 mm); the negative value places the effective load centre inside the cone backface. Cage Location relative to backface (Aa): 0.03 in. Cage Location relative to frontface (Ab): 0.11 in.

Quantity and configuration:

Unit Quantity: 1 Pc. Cone only — inner ring, rollers and cage. The matching cups are the Timken 382 and 382A.

Interchange guidance:

389 is an inch tapered roller cone number on the common industry dimensional standard, so a 389 from another inch-series maker carries the same bore, width and raceway angle. The Class 3 tolerance is a Timken execution, so a standard-tolerance 389 matches the envelope but not the running accuracy. Cross-references: Koyo 389, NTN 4T-389, NSK 389, Bower / BCA 389, Fersa 389.